Does an Upsert violate the Single Responsibility Principle?
design-patterns, oop, sql, sql-server, stored-procedures
Solution
Personally I don't believe that this principle applies completely in SQL Server. Stored procedures don't always perform just one action (and I think the notion that a stored procedure is equivalent to a class is flawed). I don't think it makes sense to split every single statement in a stored procedure into its own stored procedure. You can get absolutely ridiculous with this.
There is a balance of course, as you can be ridiculous the other way. You don't want a stored procedure with 18 different ways to specify parameters so that it can do 540 different things based on the combinations.
For an UPSERT I would still suggest that a single stored procedure is fine for this. If you want to feel better about it serving a single purpose, change your update/insert into a single `MERGE`. :-) That said, and in all seriousness, be very careful with `MERGE`.
Problem
I like to use Upsert stored procedures that update records if they exist or insert them if they don't. Without them, I would need to first find out if the record exists, and then have two separate stored procedures that I would call based on the result. I never really thought about the issue before today when I was creating a stored procedure called UpdateOrDeleteRow. As soon as I found myself including "Or" in the name, my SRP spider sense kicked in, and I realized that the upserts are basically the same thing. Is this a violation of SRP? If so, is it acceptable? If not, what should I do? I realize that the SRP is an OOP principle, and T-SQL is not an OOP language, but the basis for the principle seems like it should apply here as well.